1. Field of the Invention
The present invention relates to a facsimile apparatus, and in particular, to a facsimile apparatus provided with a printer function which is capable of connecting to an external computer.
2. Description of the Related Art
Recently, there has been proposed a facsimile apparatus 200a provided with interface means for connection with an external computer 201 for the purpose of using a printer function section of the facsimile apparatus as a printer apparatus for the external computer.
FIG. 4 shows the conventional facsimile apparatus 200a provided with the printer function. First of all, an operation of an image scanner section 300 will be now described with reference to FIG. 4.
Referring to FIG. 4, documents or originals 101 to be read is placed on a document setting section 100 on which a plurality of documents 101 can be placed. The documents 101 are transferred one by one onto a paper supply roller 102 by means of a document pick up roller 120. The paper supply roller 102 feeds the document 101 transferred one by one into a reading unit 103 of the facsimile apparatus 200a. The reading unit 103 is constituted by integrating, in a form of unit, a contact type CCD image sensor for reading an image of a document scanning the image of the document in a main scanning direction and converting the image into an image signal, an LED array for illuminating the document 101, and an optical system for focusing reflected light from the document 101 onto the CCD image sensor. By moving the document 101 on the reading unit 103, an image of the document 101 is scanned in a sub-scanning direction so as to be read. The document after reading the image of the document is fed by a document exhausting roller 104 so as to be successively ejected onto a document exhausting tray 105.
Next, the following describes an operation of a printer section 301.
A plurality of printing papers 108 are set into and held by a printing paper cassette 109. A paper supply pickup roller 122 transfers the printing papers 108 one by one to a paper supply roller 110. Then, the paper supply roller 110 supplies the printing papers 108 fed one by one towards a photoconductive drum 111 provided within the facsimile apparatus 200a. The photoconductive drum 111 rotating in a direction indicated by an arrow S is electrically charged uniformly with electric charges by an electric charger 112. A beam of laser light modulated according to an image signal is emitted from a laser scanner unit 121 including a semiconductor laser, a polygon mirror and an optical system. A beam of emitted laser light is reflected on a mirror 113, and is scanned in a direction of an axis of the photoconductive drum 111 on the surface of the photoconductive drum 111, so as to form an electrostatic latent image onto the photoconductive drum 111. A developing unit 114 develops the electrostatic latent image formed on the photoconductive drum 111 with toner so as to form a toner image thereon. The toner image formed on the photoconductive drum 111 is transferred onto the printing paper by means of a transfer charger 115. Furthermore, toner cleaner 116 collects the toner remaining on the photoconductive drum 111.
The toner image formed on the printing paper is thermally fixed on the printing paper 108 by a fixing roller 117. The printing paper 108 on which the image of the document has been printed is ejected out of the facsimile apparatus 200a by a paper exhausting roller 118, and then, the printed printing paper 108 is successively stacked on a printing paper exhausting tray 119. The above-mentioned image forming process is an electrophotographic process which is well-known to those skilled in the art.
Then the following describes an electric operation of the conventional facsimile apparatus 200a provided with the printer function with reference to FIG. 5 showing a block diagram of the conventional facsimile apparatus 200a provided with the printer function shown in FIG. 4.
Referring to FIG. 5, a microprocessor unit (referred to as an MPU hereinafter) 151 controls the entire conventional facsimile apparatus 200a shown in FIGS. 4 and 5. A bus 163 is provided for connection with the MPU 151, and the bus 163 is connected to the followings:
(a) a read only memory (referred to as a ROM hereinafter) 152; PA1 (b) a random access memory (referred to as a RAM hereinafter) 153; PA1 (c) a direct memory access controller (referred to as a DMAC hereinafter) 154; PA1 (d) a scanner control unit (referred to as an SCU hereinafter) 155; PA1 (e) a printer control unit (referred to as a PRU hereinafter) 156; PA1 (f) an encoder and decoder circuit (referred to as a CODEC hereinafter) 157; PA1 (g) an image memory 158 of a RAM; PA1 (h) a communication control unit (referred to as a CCU hereinafter) 159; PA1 (i) a host interface 160; and PA1 (j) a font memory 161. PA1 receiving means, operatively connected to a communication line, for receiving facsimile image data which is encoded according to a predetermined first facsimile coding method and is transmitted from a further facsimile apparatus of the other party; PA1 interface means, operatively connected to an external computer, for interfacing said facsimile apparatus with said external computer and receiving facsimile image data which is encoded according to a predetermined second facsimile coding method and is transmitted from said external computer; PA1 decoding means for decoding the facsimile image data received by said interface means into image data and for decoding the facsimile image data received by said receiving means into image data; and PA1 printer means for forming an image of the image data on a paper in response to the image data decoded by said decoding means. PA1 printer means for forming an image of image data in response to inputted image data; PA1 image reading means for reading an image of a document and converting the read image of the document into image data; PA1 encoding means for encoding the image data converted by said image reading means into first facsimile image data according to a predetermined first facsimile coding method, and for encoding the image data converted by said image reading means into second facsimile image data according to a predetermined second facsimile coding method; PA1 transmitting means, operatively connected to a communication line, for transmitting the first facsimile image data encoded by said encoding means to a further facsimile apparatus of the other party; and PA1 interface means, operatively connected to an external computer, for interfacing said facsimile apparatus with said external computer and transmitting the second facsimile image data encoded by said encoding means to said external computer. PA1 interface means, operatively connected to an external computer, for interfacing said facsimile apparatus with said external computer, receiving facsimile image data and digital data transmitted from said external computer and transmitting facsimile image data and digital data to said external computer; PA1 modulator and demodulator means operatively connected to a communication line, said modulator and demodulator means having a facsimile MODEM mode and a data communication MODEM mode, for, in said facsimile MODEM mode, modulating a carrier signal according to facsimile image data received by said interface means and demodulating a modulated carrier signal according to facsimile image data received through said communication line, and for, in said data communication MODEM mode, modulating a carrier signal according to digital data received by said interface means and demodulating a modulated carrier signal according to digital data received through said communication line; PA1 switching means for switching over the MODEM mode of said modulator and demodulator means between the facsimile MODEM mode and the data communication MODEM mode in response to command data transmitted from said external computer through said interface means; and PA1 printer means for forming an image of image data on a paper in response to facsimile image data demodulated by said modulator and demodulator means, and image data received from said external computer through said interface means. PA1 receiving means, operatively connected to a communication line, for receiving facsimile image data which is encoded according to a predetermined first facsimile coding method and is transmitted from a further facsimile apparatus of the other party; PA1 interface means, operatively connected to an external computer, for interfacing said facsimile apparatus with said external computer, receiving facsimile image data which is encoded according to a predetermined second facsimile coding method and is transmitted from said external computer, and transmitting to said external computer facsimile image data which is encoded according to the second facsimile coding method; PA1 decoding means for decoding the facsimile image data received by said interface means into image data and for decoding the facsimile image data received by said receiving means into image data; PA1 image reading means for reading an image of a document and converting the read image of the document into image data; PA1 encoding means for encoding the image data converted by said image reading means into first facsimile image data according to the first facsimile coding method, and for encoding the image data converted by said image reading means into second facsimile image data according to the second facsimile coding method; PA1 transmitting means, operatively connected to said communication line, for transmitting the first facsimile image data encoded by said encoding means to the further facsimile apparatus of the other party; and PA1 printer means for forming an image of the image data on a paper in response to the image data decoded by said decoding means. PA1 interface means, operatively connected to an external computer, for interfacing said facsimile apparatus with said external computer, receiving facsimile image data and digital data transmitted from said external computer and transmitting facsimile image data and digital data to said external computer; PA1 modulator and demodulator means operatively connected to a communication line, said modulator and demodulator means having a facsimile MODEM mode and a data communication MODEM mode, for, in said facsimile MODEM mode, modulating a carrier signal according to facsimile image data received by said interface means and demodulating a modulated carrier signal according to facsimile image data received through said communication line, and for, in said data communication MODEM mode, modulating a carrier signal according to digital data received by said interface means and demodulating a modulated carrier signal according to digital data received through said communication line; PA1 switching means for switching over the MODEM mode of said modulator and demodulator means between the facsimile MODEM mode and the data communication MODEM mode in response to command data transmitted from said external computer through said interface means; PA1 decoding means for decoding facsimile image data, which is encoded according to a predetermined first facsimile coding method and transmitted from the further facsimile apparatus of the other party through said modulator and demodulator means, into image data, and for decoding facsimile image data, which is encoded according to a predetermined second facsimile coding method and transmitted from said external computer through said interface means, into image data; and PA1 printer means for forming an image of image data on a paper in response to image data decoded by said decoding means. PA1 interface means, operatively connected to an external computer, for interfacing said facsimile apparatus with said external computer, receiving facsimile image data and digital data transmitted from said external computer and transmitting facsimile image data and digital data to said external computer; PA1 modulator and demodulator means operatively connected to a communication line, said modulator and demodulator means having a facsimile MODEM mode and a data communication MODEM mode, for, in said facsimile MODEM mode, modulating a carrier signal according to facsimile image data received by said interface means and demodulating a modulated carrier signal according to facsimile image data received through said communication line, and for, in said data communication MODEM mode, modulating a carrier signal according to digital data received by said interface means and demodulating a modulated carrier signal according to digital data received through said communication line; PA1 switching means for switching over the MODEM mode of said modulator and demodulator means between the facsimile MODEM mode and the data communication MODEM mode in response to command data transmitted from said external computer through said interface means; PA1 decoding means for decoding facsimile image data, which is encoded according to a predetermined first facsimile coding method and transmitted from the further facsimile apparatus of the other party through said modulator and demodulator means, into image data, and for decoding facsimile image data, which is encoded according to a predetermined second facsimile coding method and transmitted from said external computer through said interface means, into image data; PA1 image reading means for reading an image of a document and converting the read image of the document into image data; PA1 encoding means for encoding the image data converted by said image reading means into first facsimile image data according to the first facsimile coding method, said first facsimile image data being transmitted through said modulator and demodulator means and said communication line to said further facsimile apparatus of the other party, and for encoding the image data converted by said image reading means into second facsimile image data according to the second facsimile coding method, said second facsimile image data being transmitted through said interface means to said external computer; and PA1 printer means for forming an image of image data on a paper in response to image data decoded by said decoding means.
The ROM 152 stores not only a control program for controlling the facsimile apparatus 200a which is executed by the MPU 151 but also control data required when executing the control program. The RAM 153 is used as a work area required by the MPU 151. The SCU 155 executes an image signal processing process for processing an image signal sent from the image scanner section 300, such as a shading correction process, a binarizing process or the like. The PRU 156 controls a printing process of the printer section 301 by outputting an image signal to the printer section 301 in synchronous with the printing process of the printer section 301.
On the other hand, the CODEC 157 executes encoding and decoding of the image signal. The image memory 158 stores image data in a form of bit map, which are obtained by converting the encoded facsimile image data or print data sent from an external computer 201 into bit map data.
The CCU 159 executes communication control through a telephone line 164. The DMAC 154 is provided for use in transmitting image data among the CCU 159, the image memory 158, the CODEC 157, the SCU 155, and the PRU 156. The DMAC 154 is provided with a plurality of DMA channels. The host interface 160 executes transmission and reception of data with the external computer 201 according to an RS-232C protocol through an RS-232C line, which is an electric standard line for serial communication well known to those skilled in the art. The font memory 161 stores outline font data for use in converting character code data input from the external computer 201 into bit map data.
The following describes a control flow of the image signal in the stage of transmitting a document image through facsimile transmission.
An image signal read by the image scanner section 300 is input to the SCU 155, which then performs the binarizing process for the image signal and outputs binarized image data. The binarized image data sent from the SCU 155 is transferred every horizontal scanning line to the CODEC 157 through a DMA transfer by the DMAC 154. The CODEC 157 encodes the binarized image data sent from the SCU 155 so as to generate encoded facsimile image data. The encoded image data is transferred to the image memory 158 through a DMA transfer by the DMAC 154. When the encoded facsimile image data of one page of the document is stored in the image memory 158, the encoded facsimile image data of one page is transferred to the CCU 159 through a DMA transfer by the DMAC 154, and then the CCU 159 transmits the encoded facsimile image data in a form of a facsimile image signal through the telephone line 164 to a further facsimile apparatus of a destination.
Then, the following describes a control flow of the image signal in the stage of receiving a document image through facsimile reception.
Encoded facsimile image data are received by the CCU 159 from the further facsimile apparatus of the destination through the telephone line 164, and then the CCU 159 transfers the encoded facsimile image data to the image memory 158 through a DMA transfer by the DMAC 154. When the encoded facsimile image data of one page of the document is stored in the image memory 158, the printer section 301 is activated. The DMAC 154 successively transfers the encoded image data of one page stored in the image memory 158 to the CODEC 157 through a DMA transfer. The CODEC 157 decodes the encoded facsimile image data. The DMAC 154 transfers line by line image data decoded by the CODEC 157 to the PRU 156 through a DMA transfer. The PRU 156 outputs the decoded image data to the printer section 301 so as to print an image of the decoded image data.
Next, the following describes an operation of recording or printing print data sent from the external computer 201 by means of the printer section 301 of the conventional facsimile apparatus 200a. The print data sent from the external computer 201 is received by the host interface 160 through the RS-232C line 162. The print data includes a character code, a printer control code, and so forth. These print data is analyzed by the MPU 151. The outline font data is read out, in the case of necessary, from the font memory 161, and is converted into bit map data which are then stored in the image memory 158. After a print image of one page is converted into bit map image data, the DMAC 154 transfers line by line the bit map image data of one page from the image memory 158 to the PRU 156 through a DMA transfer. The PRU 156 outputs bit map print image data in synchronous with the operation of the printer section 301. This operation of recording or printing print data sent from the external computer 201 by the printer section 301 of the conventional facsimile apparatus 200a is disclosed in, for example, the Japanese patent laid-open publication No. 1-294071.
It is further proposed in, for example, the Japanese patent laid-open publication No. 3-210870, that the external computer 201 utilizes a facsimile modulator and demodulator (a modulator and demodulator is referred to as a MODEM hereinafter) provided in the CCU 159 through the host interface 60 so as to allow communication through the telephone line 64 to be performed in the above-mentioned conventional facsimile apparatus 200a provided with the printer function.
However, in the above-mentioned arrangement of providing the printer function for the conventional facsimile apparatus 200a, it is necessary to provide a memory for storing outline font data, as well as hardware or a high-performance microprocessor for generating raster data or bit map image data from the outline font data, resulting in increase in the manufacturing cost.
In order to solve the above-mentioned problem, it can be considered that the external computer 201 generates bit map data and outputs the bit map data to the facsimile apparatus 200a provided with the printer. However, the above-mentioned method has such a drawback that the amount of image data to be transferred from the external computer 201 to the conventional facsimile apparatus 200a provided with the printer increases, resulting in significantly increase in the data transmission time.
It can be further considered that the external computer 201 compresses the bit map data through an encoding process in order to reduce the amount of data. However, in the above-mentioned case, in the conventional facsimile apparatus 200a provided with the printer function, it is necessary to provide decoding means for decoding bit map data, resulting in increase in the manufacturing cost.
Furthermore, when using the document reading function of the facsimile apparatus 200a provided with the printer from the external computer 201, there is a remarkably great amount of image data outputted from the facsimile apparatus 200a provided with the orinter to the external computer 201. The above-mentioned arrangement has been accompanied by such a problem that a long data transmitting time is required.
Furthermore, in the conventional construction in which the external computer 201 communicates with a remote computer by means of a facsimile MODEM in the facsimile apparatus 200a provided with the printer, only communication in a half-duplex mode is permitted, and no standard has yet been established for error correction in the facsimile MODEM. In addition to this, it is impossible to perform the communication unless the remote computer of the other party employs a facsimile MODEM. In order to dissolve the above-mentioned problem, it can be considered to further provide a data MODEM for data communication purpose in the facsimile apparatus 200a provided with the printer function. However, when such a construction is adopted, this results in increase in the manufacturing cost.